Range scoring system

ABSTRACT

There is disclosed a preferred embodiment of a semi-automatic range scoring system which utilizes a closed-circuit television system in combination with a light pen unit and computer. The observer uses the light pen to mark the point of weapon impact on a T.V. monitor screen for each of the camera displays. Each marking causes the light pen unit to transfer digital positional information of the point of impact to the computer. Once the impact has been marked twice, the computer immediately processes the positional data to determine miss-distance and display same. The system is also adaptable for scoring miss-distance with regard to a moving target. In both cases, miss-distance information is obtained on an almost simultaneous basis with the impact of the weapon.

weasel Felt. is, new

[ RANGE SCORING SYSTEM [75] Inventors: John A. Ripley, Newport Beach;

Homer B. Davis, Long Beach, both of Calif.

[73] Assignee: Celesco Industries lnc., Costa Mesa,

Calif.

221 Filed: Nov. 20, 1972 i [21] Appl. No.: 307,377

[52] US. Cl 1178/68, 35/102, 178/DIG. 20,

l78/DIG. 36, 235/615 S, 273/1022 R, 273/DlG. 28, 340/324 A [511 lnt.C1,... A631) 63/00, 606g 7/80, H04n 7/18 [58] Field of Search ..l78/6.8,DIG. l, DlG. 20. l78/DIG. 22, DIG. 35, DIG. 36, DIG. 38, l78/DIG. 21;235/615 S; 35/102; 340/324 A, 324 AD; 273/1022 R, 27 2 5 DI 2.8

[56] References Cited UNITED STATES PATENTS 1,959,702 5/1934 Barkerl78/DIG. 1

3,147,335 9/1964 Guerth 3,256,516 6/1966 Melia 340/324 A 0 y AXISAIRCRAFT RUN-IN LlNE OTHER PUBLICATIONS Popular Mechanics, April 1943,page 5, lvlikes Score Accuracy in Bombing Practice.

Primary Examinerl-loward W. Britton Attorney, Agent, or Firm'lipton D.Jennings [5 7 ABSTRACT There is disclosed a preferred embodiment of asemiautomatic range scoring system which utilizes a closed-circuittelevision system in combination with a light pen unit and computer. Theobserver uses the light pen to mark the point of weapon impact on a T.V.monitor screen for each of the camera displays. Each marking causes thelight pen unit to transfer digital positional information of the pointof impact to the computer. Once the impact has been marked twice, thecomputer immediately processes the positional data to determinemiss-distance and display same. The system is also adaptable for scoringmissdistance with regard to a moving target. in both cases,miss-distance information is obtained on an almost simultaneous basiswith the impact of the weapon.

CAMERA CAMERA PATENTED T I 3. 793 .48 1

sum 5 OF 9 #IAXIS AIRCRAFT RUN-IN LINE CAMERA CAMERA PATENTEDFEBWIW3.793.481

SHEEI' 5 [IF 9 AIRCRAFT .RUN-IN LINE MOVING TARGET LOCATION AX'AXIS xAXIS CAMERA CAMERA L HOLD PATENTEU 9*974 3,793 I481 SHEH "90F 9 WWINPUTS FROM LIGHT PEN uNIT 54 -/04 vIDEO SWITCHING /0 SIGNAL I SI N ICHANGE CALIBRATION (SET) CONSTANT I I 9 REGISTER M0 (SET) I l SIGN SIGN[/24 f A v V V IvIuLT. flo O Ofi/ I E RS I OEI LOGIC L TAN e l IZZJCALCULATION l HOLD //6 CONTROL SIGN CALIBRATION l LOGIC 1 CHANGECONSTANT J (SET) (SET) 95 I REG DATA HOLDII-4I M6 V SIGN SlGN v AN G lMAGNITUDE V LOGIC MULT- CALIBRATION H CONVERSION 4/24 DATA I /zz I HOLD2 I SI N'CHANGE CALIBRATION I I (SET) CONSTANT I S REGISTER (SET) 2 2 I//Z4 A267 SIGN SIGN TAN G MAGNITUDE 7 MuL H4 CONVERSION LOGI CALCULATIONI DATA SIGN CALIBRATION I HOLD CHANGE CONSTANT I (SET) (SET) I 6-REGISTER l I T SIGN MAGNITUDE SlGN MULT TAN 9 CONVERSION LOGIC ZCALCULATION I /z.z L24 lZ' l DATA PAIEIIIEIIIEBI I afiscmel SHEET 8 0F 9TARGET sIzE CoNsTANTIsET CALCULATE SIGN CHANGE (SET) I FOR RUN INDIRECTIDN (sET) CALCULATE INPUT SELECT (SET) I (SET) 4 I l /30 134 /ZB fv V f L35) CALCULATE DI'STAN E V DISPLAY l S TQKl I E AXIS AND CLOCCKD'SPLAY RoTATE LOGIC CAMERA CODE cooRDINATEs DISPLAY I i J /38 DISPLAYCAMERA DISTANCE I CONSTANT (sET) x VARIABLE v TARGET i L CENTER 525 lCALCULATION /50 I CALCULATE I OVER/AUNDER AXIS PIIIIIAT I L C0oRDINATEsD I RANGE sconnvo SYSTEM BACKGROUND OF THE INVENTION The presentinvention relates to a range scoring system for scoring accuracy ofair-to-ground weapons and, more particularly, to an improved rangescoring system utilizing a precision video subsystem and automaticcomputation of miss distance.

Various range scoring systems are knowm for scoring the accuracy ofair-to-ground weapons, such as bombs, rockets, missiles, and the like.The present manual system typically employs a pair of optical sightingmeans at fixed spaced locations on the range by which two differentangles of weapon impact are determined. The coordinates of impact arethen derived by triangulation or the use of routine trigonometricequations. Another type of system uses a pair of spaced televisioncameras whose baselines form a right angle. The weapon impact isrecorded by both cameras on video tape. The tape is then played back andthe point of impact seen by each camera is measured on a grid. Themeasurement-data are then fed into a computer to determine missdistances.

The problem with the prior art techniques is that they are primarilymanual in nature and thus susceptible to human error in the making ofmeasurements or the sighting of angles, which naturally leads to errorsin the resulting miss distance solution. Furthermore, the computationsof miss distances and the like are obtained generally well after time ofimpact instead of simultaneously therewith. This delay is particularlydisadvantageous where subsequent weapon firings or launchings must beretarded until the results of the prior firing have been received. Otherforms of prior-art systems are generally limited in range or cannotreadily score different types of targets, or are susceptible to weapondamage.

The need, therefore, exists for a range scoring system in which thepossibility of human error is held to a minimum and which providesimpact coordinates or miss distances on essentially a real-time basis.

SUMMARY The present invention overcomes the problems of prior-art rangescoring systems by providing an improved system which is semi-automaticand in which the likelihood of human error is reduced by eliminatingmanual distance and angle measurements relative to weapon impact and byproviding impact positional information on an almost simultaneous basis,such as coordinates of the impact point, or the distance and angle bywhich the point of weapon impact missed the range center or otherreference point.

In accordance with the purposes of the invention, as embodied andbroadly described herein, the scoring system for a target range includesmeans for viewing said range and the impact of weapons when such occur,means for displaying the output of said viewing means, a light pen unitresponsive to the receipt of said viewing means output and the displayof said displaying means for generating signals respresentative ofimpact location, and means for receiving said signals generated by saidlight pen unit and calculating impact position.

The invention consists in the novel circuits, systems, parts,constructions, arrangements, combinations, and improvements shown anddescribed. The unique features and advantages of the invention willbecome apparent by reading the following description which, taken inconjunction with the accompanying drawings which are incorporated in andconstitute a part of the specification, disclose preferred embodimentsthereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of atarget range and certain of the apparatus employed in the presentinvention;

FIG. 2 is a block diagram of the improved scoring system forming thepresent invention;

FIG. 3 is a block diagram of pertinent portions of the light pen unitshown in FIG. 2;

FIGS. 4L7 are plan views of target ranges used in explaining operationof the present invention;

FIGS. 8A and 8B together present a block diagram of the computer shownin FIG. 2; and

FIG. 9 is a preferred embodiment of the control logic of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference will now be made indetail to the present preferred embodiments of the invention, examplesof which are illustrated in the accompanying drawings.

Referring now to the drawings, FIG. I presents a perspective view of atypical target range I0, together with certain of the apparatus employedin the present invention. The range is shown here as having a targetcircle I2 of a known radius and whose center forms the target center I4.As an example, the radius of the target circle can be 2,000 feet.

In accordance with the present invention, there are means provided forviewing said range and the impact of weapons when they occur. Asembodied herein, a pair of television cameras I6 and I0 are positionedon the range I0 to view the target area within circle I2. Cameras I6 andIS are aimed at the target center I4, and the imaginary lines runningfrom the target center to each camera I6 and I8 are called the camerabaselines 20 and 22, respectively. Preferably, the camera baselines arepositioned an equal distance back from the target center along theirrespective baselines. An example of this distance is 6,000, feet.

The cameras are preferably positioned so that their baselines 20 and 22coincide with the range coordinates or at 45 to these coordinates. Asshown in FIG. I, the cameras I6 and I8 have been positioned at 45 to therange coordinates. In all, eight possible camera locations can beselected in which the camera baselines coincide with or are 45 to therange coordinates, which provides substantial system flexibility.Assuming for ease of discussion that range 10 is a bombing range, thenthe X-coordinate 24 can be the aircraft approach or run-in line, and theY-coordinate 26 is thus perpendicular to this run-in line. The camerabaselines thus coincide with the run-in line coordinates, or are at 45thereto. It should be understood, however, that other baseline/run-inline angles can also be accommodated, In fact, angles of camera baselineto run-in line between 0 and can be selected, but such angles must thenbe compensated for in computing miss distances, as later described.

In accordance with the invention, there are means for displaying theoutput of said viewing means. As embodied herein, the outputs of thecameras 16 and 18 are applied to the input of a remote video monitor 28.Each output comprises a composite picture signal including synchronizingpulses which is transmitted to the monitor 28. The monitor 28 isenlarged at the left of FIG. 1 to illustrate an observer 34 viewing thedisplay screen 36 of the monitor 28 and using a manual probe 38 tomanually mark the point of weapon impact by noting the origin of theimpact cloud, the effect of this being hereinafter explained. Theparticular communication link between the cameras and the monitor whichis preferred is a low-loss coaxial cable, shown as cables 30 and 32 inthe drawing, although other conventional links, such as an RF link, canobviously be used.

The cameras 16,18 cables 30,32, and monitor 28 in effect define aclosed-circuit television system. In preparing the system for operation,each camera is preferably boresighted to an alignment target (not shown)temporarily placed at the target center 14. Boresighting is accomplishedby moving a camera until the target center is in the electronic centerof the video picture of the monitor 28. Each camera lens is preferablychosen such that the field-of-view of target 12 fills approximately 85percent to 95 percent of the monitor screen. Ideally, one camera istilted slightly upward and the other camera is tiled slightly downward.As a result, the range as seen by one camera fills the bottom half ofthe monitor screen, and the range as seen by the other camera fills thetop half of the screen. This serves as an aid to the observer in markingtargets. Alignment targets (not shown) can be placed on the edge of thetar get, tangent to the edge of the camera field-of-view, to providereference points to calibrate or check the calibration of a computerused to automatically calculate weapon impact position. Afterboresighting, the cameras are preferably locked in the boresightedposition on the camera mounts.

In the selection of system components, precision apparatus is preferred.For example, cameras which have good linearity minimize systeminaccuracy. Similarly, the monitor 28 should have good linearity andvisual acuity so that accurate measurement can be derived from themarkings of the probe 38. Monitor 28 is conventional in construction andincludes a cathode ray tube (not shown) positioned such that itselectron beam is directed against the inside of screen 36 during thescanning of a frame.

In the operation of the present system, to the extent to which it hasbeen described, assume an airplane 40 flies over the target circle 12along run-in line 24 and drops a bomb which impacts and explodes atpoint 42. The picture from camera 16 is simultaneously displayed onscreen 36 and the observer immediately marks the impact point bycontacting the point of his probe 38 to the impact point displayed onthe screen. The picture from camera 18 is now switched into monitor 28,replacing the picture from camera 16 on screen 36. The observer 34 nowmarks the impact point, as viewed by camera 18, with probe 38. The datafrom these two markings are immediately presented to the computer, aslater described, and miss distance or the like is immediately calculatedand displayed.

In FIG. 2, there is shown a block diagram of the present inventionincluding the electronic apparatus additional to the cameras 16 and 18and the monitor 28 previously described. As embodied herein, the outputof camera 16 and the output of camera 18 are both applied to the inputof video switch 44. The purpose of video switch 44 is to selectindividually the composite video signal of the target area beingtransmitted by either camera 16 or camera 18 and apply it to monitor 28for display. Video switch 44 is conventional in construction and can bea high-performance reed switch assembly which switches the centerconductor of the video cable. If desired, a special-effect picturesplitter can be used in place of the video switch which would split thevideo presentation on monitor 28 between the output of camera 16 and theoutput of camera 18.

The output of video switch 44 is connected to the video equalizationamplifier 46. Amplifier 46 is also of a conventional construction, andits primary function is to compensate for high-frequency losses causedby video cable 30 or 32 so that the composite video signal applied tomonitor 28 is returned to its original quality.

In accordance with the invention, a light pen unit is provided which isresponsive to the receipt of the viewing means output and the display ofthe displaying means to generate signals representative to impactlocation. As embodied herein, a light pen unit 50 is connected betweenthe output of amplifier 46 and the input of monitor 28. The light penunit includes manual probe 38 capable of being disposed adjacent to theoutside of screen 36 to sense or detect the passage of the electronduring scanning. Preferably, the probe 38 is connected to aphotosensitive detector which is used in a manner described hereinafter.

In accordance with the invention, means are provided for receiving thesignals generated by the light pen unit 50 and calculating impactposition. As embodied herein, the receiving and calculating means 52automatically processes the digital signals applied from light pen unit50 so that impact position can be calculated and displayed. Preferably,such means 52 is a digital computer which performs the basic geometriccalculations necessary to determine impact position and displays thisanswer in the desired coordinates, as de scribed in detail hereinafter.

In accordance with the invention, there are also provided means foractuating the video switch 44 so that the composite picture signal fromthe pair of cameras 16 and 18 is sequentially applied to monitor 28. Asembodied herein, computer 52 is connected to video switch 44 by line 54so that the switching between cameras 16 and 18 is automaticallyobtained once the positional information of the impact as viewed by thefirst camera has been fed to computer 52. This automatic switchingreduces the amount of time it takes an operator to manipulate probe 38to mark the impact point as viewed by both cameras 16 and 18. Thus, themarking of the monitor as viewed by the second camera, e.g., camera 18,can be performed more quickly than where switch 44 must be manuallyactuated. If desired, however, manual actuation of switch 44 can be usedan alternative to automatic switching under control of computer 52.

The light pen unit 50 is used to generate signals proportional to theX-Y coordinates of any point on the screen 36 of monitor 28. Thecoordinates are fixed by placement of probe 38 and are simultaneouslyapplied in digital form to computer 52. Preferably, the light pen unitis of a conventional construction, and as an example can be the Model4551 light pen unit manufactured by Tektronix, Inc., of Beaverton,Oregon, the construction and operation of which is disclosed in theinstruction manual for this unit published by Tektronix, lnc. in 1971. Ageneralized block diagram of the construction of this light pen unit asit pertains to the present invention is disclosed in FIG. 3.

The video input is applied to a sync separator 68 whose output isapplied to the input of four circuits to initiate the generation ofsignals therefrom. The first horizontal sync pulse in the frame to bescanned is applied to a vertical ramp 62 which outputs an analog rampvoltage which progressively increases during the time it takes for theframe to be scanned. This output is applied to one input of a comparatorcircuit 64. Vertical counter 66 counts the horizontal sync pulses duringthe frame and its digital output is continually applied to the inputoflatch 68. When latch 68 is clocked, the count that is at its input istransferred to its output and retained. The output of latch 68 isconnected into a digital-to-analog converter 78 whose output, in turn,is connected to the second input of comparator 64.

The horizontal ramp circuit 72 provides an analog output voltage whichprogressively increases during the duration of the scan of onehorizontal line in the frame. Ramp 72 is initiated by each horizontalsync pulse in the frame. its output is applied to one input ofcomparator 741-. Horizontal counter 76 preferably includes an oscillator(not shown) an, in effect, constitutes a digital timing circuit which isactuated by each horizontal synchronizing pulse applied by syncseparator 60. Thus, horizontal counter 76 undergoes a counting cycle andaccumulates a digital count for each horizontal synchronizing pulseduring the frame. The output of counter 76 is applied to a latch circuit78 which has the same construction and function as latch circuit 68. Thedigital output of latch 78 is connected to a digital-toanalog converter88 whose output is in turn connected to the second input of comparator74. The pair of counters 66 and 76 together are responsive to the outputof sync separator 60 and thereby the output of the cameras 16 and 18 foraccumulating counts proportional to the monitor's electron beam positionduring scanning.

The output of comparators 64 and 72 are connected to the input of acursor assembly 82 which develop the signals to form the cross-shapedcursor which the light pen unit applies to the screen 36 of the monitor.The output of cursor assembly 82 is connected into the cursor mixer 84where it is mixed with the input composite video signal. The compositevideo signal including the cursor signals is applied to video amplifier86 and the output of this amplifier is sent out of light pen unit 50 tothe monitor 28.

Manual probe 38, as embodied in FIG. 3, is a light pen sized to be heldin a persons hand so as to be disposed adjacent to the screen of atelevision monitor, as mentioned previously. A fiber optics bundle ismounted inside of light pen 38 so that the front end 98 of the bundle isdisposed adjacent the tip of the light pen.

As embodied herein, the light pen unit 50 further includes aphotosensitive detector which is connected to the probe 38 to convertthe light received by the passage of the electron beam into anelectrical signal. Preferably, this detector is a photomultiplier 92which is connected to the opposite end of the fiber optics bundle 88.The photomultiplier 92 is shown separate from the light pen 38 but, ifdesired, can be enclosed within the body of the light pen. The output ofphotomultiplier 92 is connected to amplifier 94!, whose output in turnis connected to the clock input of latches 68 and 78.

In accordance with the invention, light pen unit 56 further includesmeans responsive to the output of the probe for transferring theaccumulated counts of said counters to said receiving and calculatingmeans. As embodied herein, a manually operable switch 96 is formed onsaid probe and is connected by a wire 98 to the lock or hold input ofregisters 18th and 162. The signal inputs to registers 1188 and 182 arereceived from the outputs of latch circuits 68 and 78, respectively. Thedigital outputs from each of registers 1188 and M72 are applied overlines 184 and MP6, respectively, which are connected into the inputcircuitry of computer 52. Preferably, line H84 comprises nine wires inparallel for the application of the horizontal digital count to thecomputer registers. Line 98 is also connected from the light pen unit tothe computer.

The operation of the light pen unit has to a major extent been describedin the preceding description. However, a brief review of the operationnow follows. The observer picks up the light pen 38 and places the tipof this pen lightly against the face plate covering the screen 36 of thetelevision monitor 28. Each time the scanning beam passes under the tipof pen 38 during the scan of a frame, a pulse of light is coupledthrough the fiber optics 88 to the photomultiplier 92, and an electricalpulse is sent out of photomultiplier 92, amplified, and applied as theclock signal to latch circuits 68 and 78.

At the same time, the sync separator circuit 68 is extracting thehorizontal sync pulses from the input composite video signals andapplying them to counters 66 and 76. The vertical counter 66 counts thetotal number of horizontal sync pulses in each frame. e.g., 525 pulses.It is then reset and begins a new count in response to the vertical syncpulse. The horizontal counter 76 is initiated by each sync pulse. it isreset between each scan line. Assuming 525 horizontal scan lines perframe, the horizontal counter 76 goes through 525 counting cycles foreach frame of the video signal. Thus, at any time the counts accumulatedin counters 66 and 76 are proportional to the vertical and horizontalpositions of the electron beam during its frame scan.

When the photomultiplier 92 sends a clock signal to latches 68 and 78 inresponse to the passage of the electron beam past the tip of light pen38, the digital counts which have been reached at that instant incounters 66 and 76 are passed from the input to the output of latches 68and 78, respectively. These signals are converted and applied tocomparators 64 and 74 where they are compared with the analog signalsdeveloped respectively by ramps 62 and 72. As the level of each rampattains the level of its associated converter, the comparator 64 appliesa signal to cursor assembler 82. The cursor signals are then mixed withthe composite video signals and the resultant signal is amplified andapplied to the monitor. A cursor in the shape of a cross or any otherconvenient shape now appears on screen 36 under the tip of lighpen 38.ideally, this cursor is displaced slightly to avoid errors that might becaused by visual interference by the probe or the operator's handcovering the point of weapon impact.

The frame frequency is sufficiently rapid, e.g., 30 frames per second,so that the cursor fills in rapidly on the monitor screen 36. Becausethe cursor is now referenced to the position of the light pen 38 bydetection of the electron scanning beam, the cursor can be moved overthe face of the screen in direct response to pen movement.

When an airplane passes over the range to drop a bomb, the observer 34(FIG. 1) first merely touches his light pen 38 lightly to the screen 36to generate a cursor as described above. He now moves the cursor bymovement of pen 38 across the face of the screen until the cursor ispositioned at the point of weapon impact as viewed by the observer onthe monitor screen. The observer now closes switch 96 of light pen 38which causes the registers 100 and 102 to hold the counts then beingapplied by latches 68 and 78, respectively. The digital horizontal andvertical position signals of the cursor position, and thereby the pointof weapon impact, are applied by lines 104 and 106 to computer 52. Asignal is also applied by line 98 to instruct the computer to acceptthese digital signals. Once these positional signals have been stored incomputer 52, video switch 44 switches the output of the other camera 18into monitor 28 and the observer 34 marks this new point of weaponimpact in the same manner as aforedescribed. The digital horizontal andvertical counts indicative of this new impact position are alsotransferred to computer 52.

Switch 96 can be positioned on light pen 38 to be actuated by thefinger, thumb, or other movement of the hand. Preferably, switch 96 isincorporated into the point of pen 38 so that it is closed by depressionof the point firmly against the screen 36. This simplifies the markingprocedure because the light pen is already in contact with the screenand it merely requires the application of additional hand pressureinwardly against the screen to cause the tip to be depressed. Line 98,in actuality, can be composed of two wires with the switch completingthe circuit, or, alternatively, a source of potential could be containedin pen 38. The fiber optics 88 and the line 98 are preferably containedwithin the same sheath or cable for compactness and also to lessen thelikelihood of damage to these members.

The computer 52 accepts the data from the light pen unit 50 andcalculates the coordinates of weapon impact. It then displays the answerin a format selected by the computer operator, preferably either in adistance/- clock code format or a right/left-over/under format. Withreference to FIG. 4, a Cartesian coordinate system of the range 10 isshown with the cameras baselines 20, 22 coincident with the rangecoordinates 24, 26. The aircraft run-in line is here selected as Y-axis26. A hit" or point of weapon impact 42 is also arbitrarily positionedon the range. The symbols. shown are defined as follows:

0 Hit angle angle from center of camera field-ofview to hit location 42.

D Distance from camera to center of target.

x Hit distance measured from the hit impact 42 to camera 18 opticalbaseline 22 and parallel to camera 16 optical baseline 20.

y Hit distance measured from the hit impact 42 to camra l6 opticalbaseline 20 and parallel to camera 18 optical baseline 22.

The impact coordinates of hit 42 are therefore:

By substitution, these equations become:

8 x= (D, tan 0, D tan 0, tan 0, 1+ tan 0, tan 0, 3

y (D tan 6 D, tan (a tan 6 )l(l tan 6 tan 0 4 Computer 52 solvesequations 3 and 4.

When the aircraft run-in line is not coincident with one of the rangeaxes, the coordinates must be rotated through the angle the run-in linemakes with such range axis so that the hit coordinates can be referencedto the run-in line. FIG. 5 shows a Cartesian coordinate system of therange 10 with the aircraft run-in line nonconcident with a range axis.The symbols shown are defined as follows:

(I) Coordinate rotation angle.

x Hit distance measured from the hit impact 42 to the run-in line (yaxis) and perpendicular to the run-in line.

y Hit distance measured from the hit impact 42 to the x axis, which isperpendicular to the run-in line, parallel to the run-in line. Theimpact coordinates of hit 42 are therefore: x=xcosqb+ysind 5 y=ycosxsin6 The values of x and y are found by first solving equations (3) and(4). Computer 52 also solves equations 5 and 6.

The values ofx and y, i.e., miss distance, displayed by computer 52 isin a right/left-over/under format for the examples just described. If adistance/clock code format is desired, additional computations arenecessary. With reference to FIG. 6, the additional symbols shown aredefined as follows:

R Distance from target center to hit location 42.

C Clock code as in a conventional time clock (0:00

to 12:00 oclock).

K Conversion constant to convert 360 or 2 1r radians to 12:00 oclock. Xx axis of coordinate selected to go through distance/clock codegenerator, e.g., x or x.

Y y axis of coordinate selected to go through distance/clock codegenerator, e.g., y or y.

The distance R is therefore:

and the clock code equations are:

lfX is and Y is the range ofC is 0:00 to 3:00 o'clock, and C= K arc sinlXl /R,' 8

IfXis and Yis the range ofC is 3:00 to 6:00 oclock, and C K arc sin |Y|/R 3; 9

lfX is and Y is the range of C is 6:00 to 9:00 o'clock, and C =.K arcsin lXl /R 6; 10

[UK is and Y is'(+), the range ofC is 9:00 to 12:00 oclock, and C K aresin lYi/R 9. ii

The computer also solves equations 7 through 11.

The scoring system of the present invention can also be used to scoremoving targets in addition to a stationary target. The moving targetbecomes the center of the scoring system. With reference again to FIGS.1 and 2, assume that a moving target, such as a radio-controlled tank(not shown), is moving over target range 10, and that an aircraft fliesover the range and drops a bomb aimed at the tank. The bomb impacts andexplodes on the ground (assuming a miss) at a point 4l2.

The observer 34- first marks the tank position with light pen 38 forboth cameras 16 and 13 in the same manner as has been previouslydescribed for marking an impact point. Digital information proportionalto instantaneous target position is applied by light pen unit 50 tocomputer 52. This data establishes the center the scoring system withwhich to reference weapon impact position 42. The observer next marksthe impact position with the light pen 3% for both cameras and thisdigital information is also applied by light pen unit 50 to computer 52.The computer now calculates and displays the coordinates of weaponimpact with reference to the moving target at the time of impact.

With reference to FIG. 7, a Cartesian coordinate system of the range It)is shown with the moving target location and hit 42 arbitrarilypositioned on the range. The symbols shown are defined as follows:

x, Moving target location along x axis.

y Moving target location along y axis.

x Hit location along x axis.

y I-lit location along y axis.

A x Distance from moving target to hit location measured parallel to xaxis referenced from moving target location.

A y Distance from moving target to hit measured parallel to y axisreferenced from moving target location.

The impact coordinates of hit 42 with reference to the moving target aretherefore:

A y y'i yz 13 Computer 52 solves equations 12 and 13. The x and ypositions of both the target and hit are first determined with respectto the camera axes, following the example of FIG. 4, and then rotatedthrough the angle (1) so that they are referenced to the range axes,following the example of FIG. 5.

A block diagram of computer 52 showing a mechanization which encompassessmall, large, and movable vehicle targets is shown in FIGS. 8A and 813.Computer 52 is divided into two sections 52a and 52b. Section 52b isused when the target is a moving target, otherwise only sections 52a isused. As embodied herein, each of computer sections 52a and 52b includesa pair of registers, each of said registers being connected to theoutput of the light pen unit 50 to store the count proportional toelectron beam horizontal position, namely, that derived from counter 76(FIG. 3). Preferably, section 52a includes a pair of input storageregisters I10 and 112. One of these registers, e.g., register 110,receives the digital output of counter 76 in response to the output ofthe marking of weapon impact, as viewed by camera 16. The other register112 receives the digital output of counter 76 in response to the outputof the marking of weapoin impact, as viewed by the other camera 18. Whena moving target is used, registers 110 and 112 are loaded in the samemanner with digital signals proportional to position of the movingtarget at the time of weapon impact while registers 1141 ad 116 receiveweapon impact positional data. Once the input data is received by theseregisters, it is held for processing.

lltil The remainder of computer section 52a, except for the displayapparatus, as embodied herein functions as the means for electronicallyprocessing the stored counts to calculate impact position. The remainderof computer section 52b functions as means for electronically processingthe stored counts to calculate instantaneous position of the movingtarget. Included in these processing means are means for initiatingprocessing of the contents of the register after counts have been storedin each of the registers llw, M2, 11M, and M6 which are being used.Preferably, this means includes a conventional control logic circuit 11mwhich controls the data being entered in the registers and initiatesprocessing after all inputs have been entered and stored. For example,the input signal applied on line 98 by each actuation of light pen 38causes control logic llllfl to condition sequentially each of theregisters Illlll, ll 12, 114i. and II M via the data hold line so thateach register selectively accepts in turn the digital output of counter76 via input lines MM). Control logic 118 is also connected to videoswitch 434 (FIG. 2) via line 54 so that video switch 44 is automaticallyswitched from one camera to the other following application of the countassociated with the first camera into one of the input registers ofcomputer 52. When all of the input registers have been properly loadedwith selected data, calculate signal is sent to the computation portionof the computer. A signal is also sent to the display logic whichenables it to display the calculated answer.

The vertical count applied on line 106 to control logic H6 is preferablynot used in the computations. The control logic receives only the mostsignificant bit of this digital count and determines if the observer ismarking the correct part of the screen. For example, if a camera outputis being displayed on the upper part of the monitor screen, and theobserver inadvertently marks the lower part of the screen, then the mostsignificant bit will be a One instead of a Zero and the control logicwill reject the digital data. Thus, the vertical count can be used toinsure that the correct camera or correct part of the screen is beingscored.

The computations of the computer basically follow the following order,assuming a moving target is included in the scoring system:

1. Convert input data to angles 0,, 6 6 0 referenced to the center ofthe target area.

2. Calculate Calibrated 0,, 0 6 and 6 3. Calculate Tan 0,, Tan 6 Tan 0and Tan 6 4. Calculate right/left-over/under in camera coordinates.

5. Rotate coordinates if necessary to aircraft run-in coordinates.

6. Perform moving target miss distance calculations.

7. Calculate distance/clock code.

8. Display answer for stationary target, or moving target inover/under-right/left or distance/clock code.

The function performed in each computation block of the computer blockdiagram of FIGS. 8A and 6B is now briefly described. The digital countstored in each register is proportional to 0. The Sign MagnitudeConversion llZll is necessary to convert the stored 0 to an angle 0referenced to the center of the target area. This also simplifies thecomputer calculations. The Sign Change Logic 1122 is provided in orderto change the sign of the input angle if the camera locations on therange are changed. The magnitude of the input angle 0 is calibrated forslight camera-to-camera variations in the field of view. This isaccomplished by multiplying in Multiplier 124 the input angle by aconstant which can be varied to achieve calibration. The input angle isalso multiplied by the target size scale factor whose value isdetermined by the particular camera lens used. Because tangent is themajor variable in the coordinate calculations, it is calculated at 126before entering the coordinate calculation portion of the computer.

Continuing with the functions of the computer block diagram, theCoordinate Calculator 128 accepts the tan 6 calculations, and the cameraposition distance components, and calculates the projectile hit in X andY camera coordinates. This information is then sent to the Axis Rotator130 which rotates the axis of the input camera coordinate data to thatof the aircraft run-in line or any other desired orientation. Acalculate command input to the axis rotator commands the Axis Rotator torotate the axis. If there is no calculate command, the input data willproceed through the Axis Rotator 130 without being converted. Theoutputs of the Axis Rotator go to both the Variable Target CenterCalculation 132 and the Distance/Clock Code Generator 134.

The variable target center calculations are performed in block 132 formoving target applications. The instantaneous position of the movingtarget is designated as the target center. Any other point within theoverall target area could also be designed as the target center ifdesired. This computation basically moves the center of the coordinatesystem to the specified location selected by the observer using thelight per unit. To perform computation, inputs are received whichspecify the center coordinates of the new coordinate system (location ofmoving target), and the coordinate of the projectile hit. The computedoutput is sent to the Dis tance/Clock Code Generator 134.

The Distance/Clock Code Generator 134 operates on the X, Y coordinates(over/under-right/left) to convert them to a modified polar coordinatesystem (distance/clock code). Coordinate data from fixed target andmoving target are both applied to this generator. However, only one setof inputs is accepted depending on the input select command signal whichthe operator uses to select fixed target or moving target operation.There is also a calculate input which commands the Distance/Clock Codegenerator 134 to generate its normal distance/clock code output. Ifthere is no calculate command, input data will proceed through thisblock without being converted and will go to the Display Logic 136 inthe over/underright/left format.

The Display Logic 136 converts the binary sign magnitude answer into abinary-coded-decimal output. Display Logic 136 also containsconventional logic drives for driving Displays 138 and controllingdisplay power. An input from the control logic 118 establishes when theanxwer will be displayed. Set functions in the computer are manually setprior to computer operation.

Computer 52 as has been described is seen to be a special purposecomputer designed to perform missdistance calculations. However, ifdesired, a properlyprogrammed general purpose digital computer canobviously be used. A mini-computer of the type which is in popular usetoday can also be used if supplemented by the addition of inputregisters 110, 112, 114, and 116, control logic 118, and the SignMagnitude Conversion function.

FIG. 9 shows the preferred embodiment of a control logic unit 118 incombination with the computer registers and the horizontal outputregister 1111) of the light pen unit 511. The control logic 118sequentially activates each register 1111, 112, 114, and 116 to receivethe digital information being applied on lines 104 in response to lightpen marking. The signal applied from the light pen 38 on line 98 whenswitch 96 (not shown) is closed is applied through inverter 141) to NANDgates 1 12 and 144. The output of NAND gate 142 is connected toflip-flop 14 6, and the output of NAND gate 144 is connected intoflip-flop 148. The line 1116 is preferably a single line which carriesthe most significant bit out of vertical register 1112 in the light penunit, and this line is applied to NAND gate 142 and through inverter 150to NAND gate 144.

Assuming that camera 16 (FIG. 2) is first selected by switch 4 1 and isbeing displayed on the upper half of monitor screen 36, the output fromlight pen 38 in re sponse to the marking of a target impact on thescreen is applied to gates 142 and 1 14. However, the most significantbit on line 1116 is at this time a Zero and only gate 144 is enabled.The output of gate 144 goes from a One to a Zero. Flip-flop 148 is Set,and a signal is applied out of this flip-flop to register 1111 so thatonly this register accepts the digital output from register 100.

The signal on line 98 is also routed to flip-flop 152 by line 154, andthis flip-flop changes state. The O output goes from a logic Zero to aOne and this level is applied by line 15 1 to video switch 44 (FIG. 2).The output of camera 18 is now switched into the monitor, and isdisplayed at the bottom of the screen. The target impact is againmarked. This time the most significant bit on line 106 is a One and gate142 is enabled. The signal from the light pen unit, applied on line 98,sets flip-flop 146. Register 112 is thus conditioned to receive and holdthe digital positional signals from register 1011.

The target impact has now been marked for both cameras. The Q outputs offlip-flops 146 and 148 are both Ones. The output of AND gate 156therefore rises to a One which signal is sent out as a calculate comandto the rest of the computer. The digital data stored in registers 110and 112 are thus processed, and then displayed to give miss distance.The output of gate 156 is also sent to the display logic to display theanswer.

In moving target and similar applications, registers 110 and 112preferably record data on moving target instantaneous position, whileregisters 114 and 115 are used to store target impact positional data.The last two registers are controlled by flip-flops 158 and 160,respectively. The input NAND gates 162 and 164 each have an additionalenable input which is connected to the output NAND gate 156. Thus,registers 1141 and 116 can be loaded only after registers 110 and 112have been properly loaded, at which time the output of AND gate 156 is aOne. The input signal of gate 162 is received from the output of gate144 via inverter 166. Similarly, the signal applied to gate 164 comesfrom the output of gate 142 via inverter 168. The other enable input ofgates 162 and 1641 is connected to an output of shift register 170.

Shift register serially loads Ones in response to clocking inputsapplied on line 154. Initially, this shift register is in the resetposition where all Zeros are loaded. The first clock pulse applied inresponse to actuation of the light pen in marking a target causes a Oneto be loaded into shift register 170. A One appears at output 0, Thesecond light pen marking loads another One and a One output also appearsat If there is no moving target calculation involved, then the shiftregister advances no further and gates 162 and 164 do not becomeenabled. However, for moving target applications, once registers 110 and112 have been loaded, the target impact is now marked for the firstcamera display. The signal from light pen 38 again clocks shift register170 and a One appears at output Q This enables gates 162 and 164. TheZero signal out of gate 144 is inverted at 166 and applied to NAND gate162. The output of gate 162 changes from a One to a Zero and setsflip-flop 158. Register 114 is thereby loaded with the data fromregister 100.

Flip-flop 152 is toggled by the marking signal on line 154 and thesecond camera output is now displayed. The operator marks impactposition, again clocking shift register 170. However, because Q isalready loaded with a One, there is no change in output from Q Gate 164remains enabled and the signal out of gate 142 is inverted and appliedto this gate. Its output goes to Zero to set flip-flop 161). Register116 is now conditioned to receive and hold the digital signals out ofregister 100.

The target impact has now been marked for both cameras and both inputsto AND gate 172 are a One. lts output goes to One and is used as acalculate command. The data in registers 114 and 116 are thus processed.Once the calculations are complete and have been displayed, theflip-flops and registers can be reset by depressing a manual switch.Preferably, this switch is on the shaft of light pen 38 so that it canbe readily actuated by the observer.

This invention in its broader aspects is not limited to the specificdetails shown and described and departures may be made from such detailswithout departing from the principles of the invention and withoutsacrificing its chief advantages.

What is claimed is:

1. A scoring system for a target range comprising:

a. means for viewing said range and the impact of weapons when suchoccur,

b. means for displaying the output of said viewing means,

0. a light pen unit responsive to the receipt of said viewing meansoutput and the display of said displaying means for generating signalsrepresentative of impact location, and

d. means for receiving said signals generated by said light pen unit andcalculating impact position.

2. A scoring system as claimed in claim 1, wherein:

a. said displaying means includes a video monitor having 1. a screenontowhich an electron beam is directed during the scanning of the frame, and

b. said light pen unit includes 2. a manual probe capable of beingdisposed adjacent to the outside of said screen to sense the passage ofthe electron beam during scanning. 3. A scoring system as claimed inclaim 2, wherein: a. said light pen further includes 1. a pair ofcounters responsive to receipt of said viewing means output foraccumulating counts proportional to the electron beam position duringscanning, and

2. means responsive to the output of said probe for transferring theaccumulated counts of said counters to said receiving and calculatingmeans.

4. A scoring system as claimed in claim 3, wherein:

a. said viewing means comprises 1. a pair of television cameras, theoutput of each comprising a composite picture sigial, includingsynchronizing pulses, which is transmitted to said monitor,

b. one of said pair of counters receives and counts synchronizing pulsesin said composite picture signal for each line in the frame toaccumulate a count proportional to the electron beam vertical position,and

c. the other of said pair of counters comprises a timing circuit whichis actuated by each of said synchronizing pulse received from saidcamera to accumulate a count proportional to the electron beamhorizontal position.

5. A scoring system as claimed in claim 4, wherein said light pen unitfurther includes:

a. a photosensitive detector connected to said probe to convert thelight received by the passage of said electron beam into an electricalsignal,

b. means responsive to the output of said counter and saidphotosensitive detector for latching the output of said counters at thecounts accumulated at the time the probe senses the passing of theelectron beam.

6. A scoring system as claimed in claim 5, wherein said transferringmeans includes:

a. a manually operable switch on said probe connected to transfer thelatched count of said counters to said receiving and calculating means.

7. A scoring system as claimed in claim 6, wherein:

a. said receiving and calculating means includes 1. a pair of registers,each of said registers being connected to the output of the light penunit to store a count proportional to electron beam horizontal positionin response to actuation of said manually operable switch, and

2. means for electronically processing said stored counts to calculateimpact position.

8. A scoring system as claimed in claim 7, wherein:

a. said light pen unit additionally generates signals representative ofthe instantaneous position of a moving target, and

b. said receiving and calculating means further includes:

l. a second pair of registers, each of said second pair of registersbeing connected to the output of the light pen unit to store a countproportional to electron beam horizontal position in response toactuation of said manually operable switch, and

2. second means for electronically processing the stored counts in saidsecond pair of registers to calculate instantaneous position of themoving target.

9. A scoring system as claimed in claim 7, further comprising:

a. a video switch connected to the output of said pair of cameras,

b. means for actuating said video switch for sequentially applying tosaid monitor for display the composite picture signal from said pair ofcameras.

10. A scoring system as claimed in claim 9, wherein:

a. said actuating means is connected to said electronic processing meansso that the video switch automatically switches from one camera to the116 other camera in said pair following application of said registersafter counts have been obtained in the counts associated with said onecamera into said registers representative of impact position as one ofsaid registers whereby the counts obtained viewed by both cameras.responsive to both camera outputs are sequentially 12. A scoring systemas claimed in claim 11, further derived and stored in said registers. 5comprising: 11. A scoring system as claimed in claim 10, wherein a.coaxial cables linking said cameras to said monitor said processingmeans includes: for transmission of the composite picture signals.

a. means for initiating processing of the contents of

1. A scoring system for a target range comprising: a. means for viewingsaid range and the impact of weapons when such occur, b. means fordisplaying the output of said viewing means, c. a light pen unitresponsive to the receipt of said viewing means output and the displayof said displaying means for generating signals representative of impactlocation, and d. means for receiving said signals generated by saidlight pen unit and calculating impact position.
 2. A scoring system asclaimed in claim 1, wherein: a. said displaying means includes a videomonitor having
 2. a manual probe capable of being disposed adjacent tothe outside of said screen to sense the passage of the electron beamduring scanning.
 2. means responsive to the output of said probe fortransferring the accumulated counts of said counters to said receivingand calculating means.
 2. second means for electronically processing thestored counts in said second pair of registers to calculateinstantaneous position of the moving target.
 2. means for electronicallyprocessing said stored counts to calculate impact position.
 3. A scoringsystem as claimed in claim 2, wherein: a. said light pen furtherincludes
 4. A scoring system as claimed in claim 3, wherein: a. saidviewing means comprises
 5. A scoring system as claimed in claiM 4,wherein said light pen unit further includes: a. a photosensitivedetector connected to said probe to convert the light received by thepassage of said electron beam into an electrical signal, b. meansresponsive to the output of said counter and said photosensitivedetector for latching the output of said counters at the countsaccumulated at the time the probe senses the passing of the electronbeam.
 6. A scoring system as claimed in claim 5, wherein saidtransferring means includes: a. a manually operable switch on said probeconnected to transfer the latched count of said counters to saidreceiving and calculating means.
 7. A scoring system as claimed in claim6, wherein: a. said receiving and calculating means includes
 8. Ascoring system as claimed in claim 7, wherein: a. said light pen unitadditionally generates signals representative of the instantaneousposition of a moving target, and b. said receiving and calculating meansfurther includes:
 9. A scoring system as claimed in claim 7, furthercomprising: a. a video switch connected to the output of said pair ofcameras, b. means for actuating said video switch for sequentiallyapplying to said monitor for display the composite picture signal fromsaid pair of cameras.
 10. A scoring system as claimed in claim 9,wherein: a. said actuating means is connected to said electronicprocessing means so that the video switch automatically switches fromone camera to the other camera in said pair following application of thecounts associated with said one camera into one of said registerswhereby the counts obtained responsive to both camera outputs aresequentially derived and stored in said registers.
 11. A scoring systemas claimed in claim 10, wherein said processing means includes: a. meansfor initiating processing of the contents of said registers after countshave been obtained in said registers representative of impact positionas viewed by both cameras.
 12. A scoring system as claimed in claim 11,further comprising: a. coaxial cables linking said cameras to saidmonitor for transmission of the composite picture signals.